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针对某钢厂铝镇静药芯焊丝钢拉拔频繁断丝问题,分析了断口形貌与成分,并结合生产工艺提出了断丝机理与控制措施。断口电镜分析发现:断口形貌发生扭曲分层,能谱分析表明导致分层的物质为保护渣。对比焊丝钢断丝炉次与正常炉次工艺参数发现断丝炉次液面波动小于±3 mm的比例为73%~87%,明显低于正常炉次。焊丝钢拉拔断丝机理为:由于吹氩量过大和水口结构不合理导致液面波动过大,引起结晶器保护渣卷入被凝固坯壳捕获,残留在铸坯并延续到冷轧卷。拉拔过程中钢材发生畸变分层,当拉拔力超过其能承受最大拉应力时发生断裂。从防止卷渣角度提出了控制连铸吹氩量、改变浸入式水口底部结构等措施,实施改进措施后拉拔断丝率从8.7%降至0.5%。
Aiming at the frequent drawing of aluminum killed seized Cored Wire in a steel mill, the fracture appearance and composition were analyzed. The mechanism and control measures of the broken wire were put forward in combination with the production technology. Fractograph analysis showed that: the fracture morphology distorted stratification, energy spectrum analysis shows that the material leading to stratification of mold flux. Comparison of wire and wire breakage furnace normal furnace process parameters found that the broken wire furnace fluid level fluctuations of less than ± 3 mm ratio of 73% to 87%, significantly lower than the normal furnace. Wire drawing broken wire mechanism is: due to excessive argon blowing and outlet structure unreasonable lead to excessive fluctuations in the liquid, causing the mold flux entrapped in the solidified shell capture, remain in the slab and continue to the cold rolled coil. Distortion stratification of the steel during drawing, breaking occurs when the drawing force exceeds the maximum tensile stress it can withstand. From the angle of prevention of scum, some measures are proposed to control argon blowing in continuous casting and to change the bottom structure of the submerged entry nozzle. The rate of wire breakage after drawing is reduced from 8.7% to 0.5%.